dore_m
Sympathetic resonance isn't supported I think for multiple reasons. I'm taking educated guesses here, but recording those separately increases the sampling time significantly, or audio software tricks are too complicated to isolate it. Also, applying it properly to the base samples may not be simple either.
The how to's on piano book and on the YouTube channels contain alot of detailed info about how to use kontakt to transition velocities and I had to figure them out myself for sfz. I'd say most free libraries don't go to this extent using all of those tricks. Adding sympathetic resonance is yet another step. I might look into it for the future but given that I'm sampling opp (other people's pianos) my time with them is very short and I need to optimize setup performance and takedown. It might not be feasible for me.